JPH11160166A - Calibration method and device of pyrometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly calibrate a measured temperature of a pyrometer of an elevated temperature desorption gas analyzer by calibrating a temperature T1' when the phase transition of a material generating the phase transition at a predetermined phase transition temperature T1 to be the temperature T1. SOLUTION: The pressure of an inside of a sample feeding mechanism 11, and the insides of a vacuum chamber 10 and an ionizing chamber 12 are reduced in vacuum, and a sample (a) is mounted on a mount table 14. Then the sample (a) is superheated at a high temperature by an infrared ray lamp heater 15. A temperature of the material forming a film on a surface of the sample (a) is measured by a pyrometer 16 while superheating the same. The impurity gas desorbed from the film of the surface of the sample (a) by the superheating, is introduced into the ionizing chamber 12 to analyze the mass. When the sample (a) is, for example, TiSi2 , the phases is transited from a C49 structure to a C54 structure at the phase transition temperature T1, and the supernatant gas (H2 gas) is generated from the layer. The temperature T1' at the peak of the supernatant gas is calibrated to the phase transition temperature T1 while analyzing the mass in the ionizing chamber. The correct measurement temperature after the calibration is input to a control means 18 with the information on the sample (a).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for calibrating a temperature measured by a pyrometer to an accurate temperature.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, for example, a thermal desorption gas analyzer (T) is used to analyze a film formed on the surface of a silicon substrate and impurities contained in the film.
AS device). In this thermal desorption gas analyzer, a sample is heated to a high temperature in a vacuum chamber, and the gas desorbed from the film is analyzed. Adsorbed molecules and atoms in the vicinity of the sample surface, which have obtained thermal energy by heating, desorb from the sample surface in order from those with weak adsorption power, so desorption of gas can be detected by the rise in pressure in the vacuum chamber and desorbed. By mass analysis of gas, the adsorption state on the sample surface,
Information such as surface adsorbed gas and impurities contained in the sample can be obtained.

[0005] FIG. 5 shows a system outline of a conventional thermal desorption gas analyzer 100. Inside the vacuum chamber 101, there is provided a mounting table 102 on which a sample a 'having a desired substance formed on the surface of a silicon substrate is mounted. A mounting table 102 provided in the vacuum chamber 101 from a sample feeding mechanism 103 via a gate valve 104
The sample a 'is placed on the sample. Further, the sample a ′ placed on the mounting table 102 is irradiated with infrared rays from the infrared lamp heater 105 to heat the sample a ′ to a high temperature. By this heating, in the film on the surface of the sample a '(in the substance)
The gas generated from is introduced into the ionization chamber 106 and subjected to mass analysis to determine the type. Further, the heating temperature of the sample a 'is measured by a pyrometer 107 composed of, for example, a thermocouple, a platinum thermometer, a radiation thermometer, and the like, and is input to the control means 108 together with information on the desorbed gas. An example of such a thermal desorption gas analyzer is described in, for example, the document “Vacuum, Vol. 34, No. 11 (1991)”, p. 83.

[0004]

However, the conventional pyrometer has no means for accurately calibrating the measured temperature. For this reason, when performing the analysis by the thermal desorption gas analyzer as described above, it is sometimes difficult to accurately control the heating temperature of the sample. Unless the heating temperature of the sample can be accurately controlled when performing the thermal desorption gas analysis, it is difficult to heat the sample to a desired temperature, and proper analysis cannot be performed.

Accordingly, it is an object of the present invention to provide means for accurately calibrating the measurement temperature of a pyrometer used in a thermal desorption gas analyzer or the like.

[0006]

In order to achieve this object, a first aspect of the present invention is to increase the temperature of a substance which undergoes a phase transition at a predetermined phase transition temperature T1 while measuring the temperature with a pyrometer. And the temperature T measured by a pyrometer when the phase transition occurs
A method for calibrating a pyrometer, wherein 1 ′ is calibrated so as to be the predetermined phase transition temperature T1. In the method according to the first aspect, as described in the second aspect, the substance is, for example, TiSi _2, and the phase transition can be detected by a phase transition from a C49 structure to a C54 structure. Further, as described in claim 3, an impurity is implanted into the substance, and a temperature T measured by the pyrometer when the desorption of the impurity from the substance due to the temperature rise reaches a peak.
Calibration may be performed so that 1 ′ becomes the predetermined phase transition temperature T1.

According to a fourth aspect of the present invention, the predetermined recrystallization temperature T2
The temperature of the substance to be recrystallized by measuring the temperature with a pyrometer is increased while the temperature is measured with a pyrometer, and the material is recrystallized, and the temperature T2 'measured by the pyrometer at the time of the recrystallization is calibrated so as to be the predetermined recrystallization temperature T2. This is a method for calibrating a pyrometer. In the method according to the fourth aspect, as described in the fifth aspect, the substance is Si, and the recrystallization can be detected by recrystallization from amorphous Si to crystalline Si. Further, as described in claim 6, an impurity is injected into the substance, and the temperature T2 ′ measured by the pyrometer when the desorption of the impurity from the substance due to the temperature rise reaches a peak. The calibration may be performed so as to reach the predetermined recrystallization temperature T2. In that case, the temperature of the substance may be raised in a vacuum chamber, and the recrystallization may be detected by an increase in the pressure in the vacuum chamber.

According to a seventh aspect of the present invention, there is provided a heating means for increasing the temperature of a substance which undergoes a phase transition at a predetermined phase transition temperature T1 into which an impurity has been implanted, and detecting a peak of desorption of the impurity from the substance due to the temperature increase. And a temperature T measured by a pyrometer when the peak of desorption of impurities is detected by the detecting means.
A calibrating device for calibrating the thermometer so that 1 ′ is the predetermined phase transition temperature T1.

The invention according to claim 8 is a heating means for increasing the temperature of a substance to be recrystallized at a predetermined recrystallization temperature T2 into which impurities are implanted, and detecting a peak of desorption of impurities from the substance due to the temperature increase. And a temperature T measured by a pyrometer when the peak of desorption of impurities is detected by the detecting means.
A calibrating device for calibrating the thermometer 2 ′ so as to be the predetermined recrystallization temperature T2.

[0010]

Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a thermal desorption gas analyzer 1 equipped with a calibration device according to an embodiment of the present invention.
FIG. 1 is a block diagram showing an outline of a system.

A sample feeding mechanism 11 and an ionization chamber 12 are arranged adjacent to the vacuum chamber 10. A gate valve 13 for maintaining airtightness is provided between the vacuum chamber 10 and the sample feeding mechanism 11. A mounting table 14 for mounting a sample a formed by depositing a desired substance on the surface of a silicon substrate is provided inside the vacuum chamber 10. The sample a carried into the chamber 10 is
It is designed to be placed on top of. The sample a is made of, for example, Ti having impurities implanted on the surface of a silicon substrate.
A film formed by forming a layer made of Si ₂ , or a film formed by forming BF ₂ ⁺ as an impurity on the surface of a silicon substrate to form a layer made of amorphous Si, or the like.

Below the vacuum chamber 10, there is provided an infrared lamp heater 15 for irradiating the sample a thus mounted on the mounting table 14 with infrared rays and heating it to a high temperature. The gas generated from the film on the surface of the sample a by this heating is introduced into the ionization chamber 12 and subjected to mass analysis. Further, a pyrometer 16 for measuring the temperature of the surface of the sample a mounted on the mounting table 14 is provided. The pyrometer 16 includes, for example, a thermocouple, a platinum thermometer, a radiation thermometer, and the like.
After being calibrated to an accurate temperature by the calibration means 17, the information is input to the control means 18 together with information on the substance a analyzed in the ionization chamber 12. The calibration means 17 has a phase transition temperature T of a substance formed on the surface of the sample a.
1 or a recrystallization temperature T2 (for example, a temperature T1 at which TiSi ₂ undergoes a phase transition from a C49 structure to a C54 structure or an amorphous Si
Is set at a temperature T2) at which the crystal is recrystallized into crystalline Si.

A method of calibrating the pyrometer 16 in the thermal desorption gas analyzer 1 configured as described above will be described with reference to FIG. First, the inside of the sample feeding mechanism 11 and the insides of the vacuum chamber 10 and the ionization chamber 12 are reduced to a vacuum. Then, the gate valve 13 is opened under the reduced pressure, the sample a is carried into the vacuum chamber 10 from the sample feeding mechanism 11, and the sample a is mounted on the mounting table 14 (S1). In this case, the sample a is formed, for example, by forming a layer made of TiSi ₂ into which hydrogen is implanted as an impurity on the surface of a silicon substrate, or forming a layer made of amorphous Si by implanting BF ₂ ⁺ into the surface of the silicon substrate. Film formed, and the like.

Next, the sample a is irradiated with infrared rays by the infrared lamp heater 15, and the sample a is heated to a high temperature (S2). While this heating is being performed, the temperature of the substance formed on the surface of the sample a is measured by the pyrometer 16. The impurity gas (eg, hydrogen gas) desorbed from the film on the surface of the sample a by the heating is supplied to the ionization chamber 12.
And mass analyzed (S3).

Here, if the sample a is, for example, a layer formed of TiSi ₂ into which hydrogen has been implanted as an impurity on the surface of a silicon substrate, the TiSi ₂ has a predetermined phase transition temperature T1 (about At 740 ° C.), a phase transition from a C49 structure to a C54 structure occurs, and at this phase transition, most desorbed gas (hydrogen gas) is generated from the layer. Therefore,
While performing mass spectrometry in the ionization chamber 12, the temperature T1 'measured by the pyrometer 16 when the peak of the desorbed gas occurs is input to the calibration means 17 (S4).

Next, the calibrating means 17 compares the thus inputted temperature T1 'with a preset phase transition temperature T1 of TiSi ₂ , and detects a temperature T1 measured by the pyrometer 16 when a phase transition occurs. Calibration is performed so that 'becomes the phase transition temperature T1 (S5). Then, the accurate temperature after the calibration is input to the control means 18 together with the information on the substance a analyzed in the ionization chamber 12 (S6).

On the other hand, if the sample “a” is formed by injecting BF ₂ ⁺ into a surface of a silicon substrate to form a layer made of amorphous Si, for example,
i is recrystallized at a predetermined phase transition temperature T2 (approximately 550 ° C.). During this recrystallization, most desorbed gas (eg, hydrogen gas) is generated from the layer. Therefore, while performing mass spectrometry in the ionization chamber 12, the temperature T2 'measured by the pyrometer 16 when the peak of the desorbed gas occurs is input to the calibration means 17 (S4).

Next, the calibration unit 17, thus being preset with the input temperature T2 'and recrystallization temperature T2 of the TiSi ₂ are compared, the temperature T2 measured by the pyrometer 16 when caused recrystallization Calibration is performed so that 'becomes the recrystallization temperature T2 (S5). Then, the accurate temperature after the calibration is input to the control means 18 together with the information on the substance a analyzed in the ionization chamber 12 (S6).

As described above, according to the present embodiment, the pyrometer can be easily calibrated by using a substance having a known phase transition temperature or recrystallization temperature (such as TiSi ₂ or amorphous Si). become able to. Although the description has been given based on the thermal desorption gas analyzer, the present invention also relates to an apparatus that uses a vacuum chamber and raises the temperature in the chamber, such as a CVD apparatus, a sputtering apparatus, and an etching apparatus used in a semiconductor manufacturing process. Can be suitably applied to the temperature calibration. In the embodiment, the temperature calibration is performed by detecting the peak of the desorbed gas accompanying the transformation (phase transfer or recrystallization) of a single substance such as TiSi ₂ or amorphous Si. By the reaction of more than one kind of substance, for example, the reaction of Ti and Si, TiSi _{2 of} C49 structure
It is also possible to perform temperature calibration by detecting a desorbed gas generated when forming the gas. Further, in the above embodiment, the calibration is performed by detecting the desorbed gas. However, the pressure in the vacuum chamber changes with the desorption of the impurity gas. May be detected and the temperature may be calibrated.

[0020]

EXAMPLE Next, an example of the present invention was performed. First, as a first example, a sample was prepared by forming a film of TiSi ₂ having a C49 structure with a thickness of 40 nm on a Si substrate. This sample was heated at 120 ° C./min in a thermal desorption gas analyzer,
The desorbed hydrogen gas was examined with a mass spectrometer. T on sample surface
The temperature of iSi ₂ was measured by a thermocouple. FIG. 3 shows the desorption spectrum of hydrogen (M / e = 2) of the first embodiment. The peak of desorption of hydrogen is shown at 680 ° C. measured by a thermocouple. TiSi ₂ of Example 1 was 680 ° C.
Is known to cause a phase transition from the C49 structure to the C54 structure. As a result of X-ray diffraction of this sample surface, the phase of TiSi ₂ changed from the C49 structure to the C54 structure around the above desorption temperature. It can be seen that the above desorption peak is due to the phase transition of TiSi ₂ , and the value 680 ° C. measured by the thermocouple is correct.

Next, as a second embodiment, BF is applied to a Si substrate.
₂ ⁺ by ion implantation of 60keV 50 × 10 ¹⁵ io
By implanting ns / cm ² , the substrate surface was made amorphous to prepare a sample. This sample was heated at 120 ° C./min in a heated desorption gas analyzer, and the desorbed hydrogen gas was examined by a mass spectrometer. The temperature of the sample surface was measured with a thermocouple. Hydrogen (M / e = 2), BF of this second embodiment
FIG. 4 shows desorption spectra of ₃ ⁺ (M / e = 33) and SiF ₃ ⁺ (M / e = 85). 550 measured with thermocouple
Each desorption peak is shown in ° C. It is known that amorphous Si recrystallizes at 550 ° C. As a result of reflection high-speed electron diffraction of the surface of the sample, it was found that the crystal changed from amorphous to Si crystal around the above desorption temperature. It can be seen that the above desorption peak is due to recrystallization of Si, and the measured value of 550 ° C. by thermocouple is correct.

[0022]

According to the present invention, a vacuum chamber such as a thermal desorption gas analyzer, a CVD apparatus, a sputtering apparatus, or an etching apparatus used in other semiconductor manufacturing processes is used, and the temperature is raised in the chamber. In equipment, etc.
It is possible to correctly calibrate the measurement temperature of the pyrometer.
Therefore, the sample can be accurately heated to a desired temperature.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system outline of a thermal desorption gas analyzer provided with a calibration device according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining a method of calibrating a pyrometer.

FIG. 3 is a graph showing a thermal desorption spectrum of TiSi _{2 having} a C49 structure according to Example 1.

FIG. 4 shows Si implanted with BF ₂ ^{+ according} to Example 2;
It is a graph which shows a thermal desorption spectrum of the surface.

FIG. 5 is a block diagram showing a system outline of a conventional thermal desorption gas analyzer.

[Explanation of symbols]

 a sample 1 thermal desorption gas analyzer 10 vacuum chamber 11 sample feeding mechanism 12 ionization chamber 13 gate valve 14 mounting table 15 infrared lamp heater 16 pyrometer 17 calibration means 18 control means

Claims (8)

[Claims] 1. A substance which undergoes a phase transition at a predetermined phase transition T1 is subjected to a phase transition by raising the temperature while measuring the temperature with a pyrometer, and when the phase transition occurs, the temperature T1 'measured by the pyrometer is determined by the predetermined temperature. A calibration method for a pyrometer, wherein the calibration is performed so as to have a phase transition temperature T1 of. 2. The method according to claim 1, wherein the substance is TiSi ₂ , and the phase transition is a phase transition from a C49 structure to a C54 structure. 3. An impurity is injected into the substance, and the temperature T1 'measured by the pyrometer when the desorption of the impurity from the substance due to the temperature rise reaches a peak is determined by the predetermined phase transition T1. 3. The method for calibrating a pyrometer according to claim 1, wherein the calibration is performed so that 4. A substance to be recrystallized at a predetermined recrystallization temperature T2 is heated and recrystallized while measuring the temperature with a pyrometer.
A method for calibrating a pyrometer, comprising calibrating a temperature T2 'measured by a pyrometer at the time of the recrystallization so as to be the predetermined recrystallization temperature T2. 5. The method for calibrating a pyrometer according to claim 4, wherein said substance is Si, and said recrystallization is recrystallization from amorphous Si to crystalline Si. 6. An impurity is implanted into the substance, and the temperature T2 'measured by the pyrometer when the desorption of the impurity from the substance with a rise in temperature reaches a peak is the predetermined recrystallization temperature. 6. The method for calibrating a pyrometer according to claim 4, wherein the calibration is performed so as to be T2. 7. A predetermined phase transition temperature T into which impurities are implanted.
A heating means for raising the temperature of the substance which undergoes a phase transition in step 1, a detecting means for detecting a peak of desorption of impurities from the substance accompanying the temperature rise, and a high temperature when the peak of desorption of impurities is detected by the detecting means. A calibrating means for calibrating the temperature T1 'measured by the meter so as to be the predetermined phase transition temperature T1. 8. A predetermined recrystallization temperature T at which impurities are implanted.
Heating means for raising the temperature of the substance to be recrystallized in step 2, detecting means for detecting the peak of desorption of impurities from the substance due to the temperature rise, and high temperature when the peak of desorption of impurities is detected by the detection means A calibrator for calibrating the thermometer so that the temperature T2 'measured by the thermometer becomes the predetermined recrystallization temperature T2.